WL is spectacular at Christmas, but Disney in general is wonderful during the holidays. The most striking feature is the lobby of the main Lodge, but the whole resort and its decor fit more easily into traditional ideas of Christmas.
Having said that, you can still visit WL during your visit. And how much time will you spend around the lodge? If you spend almost all of your time in other places -- the parks, your room, the pools -- the difference may be marginal. We are partial to VWL overall, so I am trying to be unbiased. It is a great place for the holidays, but any place in WDW is great at that time of the year (or any other time for that matter!).